1. Field of the Disclosure
The disclosure relates generally to a photoresist polymer, a photoresist composition, and a method for manufacturing a semiconductor device using the same. More specifically, the disclosure relates to a photoresist polymer containing a fluorine component, a photoresist composition containing the photoresist polymer and an organic solvent to reduce surface tension, and a method for manufacturing a semiconductor device using the same by forming a photoresist film uniformly on the whole surface of an underlying layer pattern to allow a subsequent ion-implanting process to be performed stably.
2. Description of the Related Technology
As the manufacturing technology of semiconductor devices has developed and the field of application of memory devices has been extended, technology has been urgently required to manufacture high-capacity memory devices of high integration. As a result, multilateral studies to improve a photo-lithography processes, cell structures, new materials which constitute wires, and physical property limits of materials which form insulating films have been made.
The photo-lithography process is essentially applied to form a contact hole for interconnecting various layers that constitute a device; thus, the photo-lithography process is required to be suggest to produce a high-integrated semiconductor device. Through the photolithography process, a fine pattern critical dimension (CD) of 0.01 μm or less can be formed with short wavelength light sources such as KrF (365 nm), ArF (193 nm) or VUV (157 nm) and chemically amplified photoresist materials having low light absorbance to the above light sources, excellent dry etching resistance, heat resistance and adhesive property.
Meanwhile, since the aspect ratio of the pattern has increased due to the decrease of the CD for high integration of semiconductor devices, the usage of conventional chemically amplified photoresist materials during the photolithography process results in limitations.
In other words, since the conventional chemically amplified photoresist materials have high viscosity due to high surface energy, when a photoresist film is formed on the whole surface of an underlying layer pattern having an increased aspect ratio, a photoresist material does not uniformly fill the pattern. As a result, a void is formed in the photoresist film (see FIG. 2), which damages the substrate during a subsequent ion-implanting process, which results in decrease of manufacturing yield of semiconductor devices.
FIGS. 1a through 1d are diagrams illustrating a photoresist pattern formed by using conventional chemically amplified photoresist materials and a ion-implanting process using the photoresist pattern.
Referring to FIG. 1a, an underlying layer (not shown) is formed on a semiconductor substrate 1, and etched to form an underlying layer pattern 3.
As shown in FIG. 1b, a photoresist film 5 is formed on the entire surface including the underlying layer pattern 3 of FIG. 1a with a conventional photoresist material (not shown).
An exposure and developing process is performed on the photoresist film 5 of FIG. 1b to form a photoresist pattern as shown in FIG. 1c. As a result, the photoresist pattern is formed to have an open portion 9 and a portion 5-1 filled with photoresist alternately between the underlying layer patterns 3. The void 7 remains in the filled portion 5-1.
An ion-implanting process is performed on the open portion 9 with the photoresist pattern of FIG. 1c as an ion-implanting process mask to form an ion-implanting region 11 as shown in FIG. 1d. Then, the photoresist pattern is removed to obtain the semiconductor substrate 1 where an ion-implanting region 11 is formed alternately in the underlying layer pattern.
Since the photoresist film having the void therein does not have a sufficient thickness to protect the semiconductor substrate from ion gas during the ion-implanting process, a subsequent ion-implanting process cannot be stably performed. As a result, an ion-implanting region 13 is formed in an undesired region as shown in FIG. 1d when the ion-implanting process is performed with the photoresist pattern as a mask, thereby degrading electric characteristics of the semiconductor device and reducing yield of semiconductor devices.
Moreover, voids are more generated in the photoresist film when an ultra-fine pattern having a high aspect ratio is formed with an exposer having many lens numerical apertures.